Tobacco smoke filtering elements



Sept. 15, 1959 J. E. KlEFER ETAL 2,904,050

TOBACCO SMOKE FILTERING ELEMENTS Filed Jan. 5, 1955 Fig.

CELLULOSEACETATE F/LAMENTS (2D/F/LAME/VT) CONTAIN/N6 WAX PARTICLES Fig.2

TOBACCO SMOKE FLOW CELLULOSE ACETATE F/LAMENT CO/VTA/AT/NG WAX PARTICLESJOHN E. K/EFER GEORGE I? TOUEY INVENTORS A TTOR/VEYS 2,904,050 TOBACCOSMOKE FILTERING ELEMENTS John E. Kiefer and George P. Touey, Kingsport,Tenn.,

, assignors to Eastman Kodak Company, Rochester,

N.Y., a corporation of New Jersey Application January 5, 1955, SerialNo. 480,059 Claims. (Cl. 131-208) Unitcd States Patent ing media.However, some fibrous materials have certain disadvantages either fromthe standpoint of their fabrication into filters or their undesirableeffect on the taste of thesmoke. For example, cotton and paper cannot betoo-conveniently processed by conventional cigarette machinery into aform that can be readily cut into filter tips and added to the. end of'a cigarette. vAnother disadvantage of tobacco smoke filters made fromcotton or paper is that moisture is absorbed quite readily by the filterwhich makes the smoke too dry.

The use ofcertain textile fibers and in particular fibers of celluloseester, overcomes to a great extent the aforementioned fabricationdifiiculties ,encountered--,with cotton or crepe paper. That is, textilefibers can be manufactured: in a formthat is easily converted by,reasonable conventional cigarette processingequipment into filter; tipswhich can 'be used for tobacco smoke filtering purposes. Thus, forexample, it is possible to orient a large number of cellulose acetatefibers into the form of a continuous cord whichv is commonly known to.the trade as a tow. Such tow can be plasticized, cut, and wrapped incigarette paper to form filter rods; with great rapidity on -a filtermake-up machine. These filter rods are then easily out into tipsof thedesired length and placed on the ends of cigarettes. While, as justmentioned, textile tow has certain advantages for manufacturing tobaccosmoke filtering elements, in some instances the resultant filter has notpossessed as much stifiness or firmness as desired. Also, there has beensome tendency of textile fibers to become soft or soggy due to theabsorption of moisture from the tobacco smoke.

After investigatingwe have found that fibrous ma terials, particularly acrimped cellulose ester typeof tow material may be treated in a simplemanner to render it possible to obtain an improved tobacco smoke filtertherefrom This invention therefore has as one object the production ofmore efiicient tobacco smoke filter elements consistingof a bundle ofcrimped substantially longitudinally oriented textile fibers, containinga wax additive. Another object is to provide means for increasing theability of the tobacco smoke filter of the class described to removemore nicotine, tars and other undesired components of tobacco smokewithout causing the smoke to be dry or distasteful. --Still anotherobject is to provide an oriented type of tobacco smoke filter elementwhich is stifier, more firm and otherwise possesses qualities mak-2,004,050 Patented Sept. 15, 1959 ing' it easier to process inconventional filter make-up machmery. Still a further object is toprovide an improved tobacco smoke filter of textile tow which whileexhibiting good filtering qualities does not tend to become soft andsoggy. A particular object of this invention is to provide a procedurefor incorporating wax into cord or tow tobacco smoke filtering elements.Other objects will appear hereinafter.

i We have found that the continuous cord or tow type of textile fibercan be substantially improved for tobacco smoke filtering purposes byadding to the crirnped tow orcord a certain amount of wax. That is, ourimproved tobacco smoke filter of the present invention consistsgene'rally of a mass of substantially longitudinally alignedcrimpedcellulose ester fibers, the spacing of substantially all groupsof adjacent fibers providing passage for tobacco smoke therethrough,said fibers carrying thereon a certain amount. of wax usually between130% based on the weight of the fibers.

Various means andprocedures may be used for coating the fibrous surfaceswith wax. Thus, for example, wax can be heated to its melting point andsprayed on the fibers. Another. method is to draw the fibers through abath containing molten Wax. Still another method is to deposit solid Waxon the cord or tow and then heat treat the cord .or tow to melt anddiffuse the wax evenly on and throughout the filter element.

.for a further understanding of certain aspects of our inventionreference may be made to the attached drawin g forming a part of theinstant application.

In this drawing, Fig. 1 is a diagrammatic illustration ri a considerablyenlarged scale of a segment of a plurality of crimped continuouscellulose acetate filaments carrying particles of waxy material on thefilaments in accordance with the present invention. .FiggZ is adiagrammatic illustration on a considerably enlarged scale of a singlecrimped cellulose acetate filamerit carrying Wax particles thereon inaccordance with the present invention.

Referring further to Fig. 1, the plurality of individual celluloseacetate filaments are shown at 1, 2 and 3. These filaments-are'substantially continuous, only a segment of a small group of suchcontinuous filaments being illustrated in the figure. These filamentscontain distinct crimps as illustrated at points 4 and 5, for example.The filaments carry particles of waxy solids firmly bonded 'to thefilaments as disclosed at 6 and 7, for example. The several thousandfilaments making up a filter would be intermingled in the rod-likefilter element substantially similar to the interminglingdiagrammatically illustrated in Fig." 1.1 I Reference is now made toFig. 2 wherein a segment of a single continuous filament is illustrated.This figure better shows some of the features referred to above. Forexample, in this figure, numeral 11 designates the cellulose acetatefilament. The peak of a crimp is generally indicated at point 12.The'solid waxy particles which are carried by the filament, whichparticles are firmly bonded thereto, are illustrated, for example at 13and 14.

In carrying out any of the above methods, it is usually desirabletospread the fibers out to a width of several inches by any suitablemethod for facilitating the uniform application of the wax to all of thefibers. After the fibers have been properly coated with wax, they arethen gathcred together into the desired configuration for the filterand'wrapped with a wrapper or otherwise somewhat more permanently formedand held in the desired shape. These latter operations of forming thefibers into the filter element may bevery readily accomplished inconventional machinery. In other words, our wax treated fibers may bebetter formed into tobacco smoke filtering elements 3 than the untreatedfibers heretofore processed in such machinery.

' In carrying out our invention, we have found that various types ofwaxes may be used. Thus, vegetable, petroleum, insect, animal, mineral,and synthetic waxes are in general satisfactory; More specifically, someof the waxes which we have found particularly useful and prefer are asfollows: (a) Carnauba wax.-This is a vegetable wax and consists chiefly(about 75 of myricyl cerotate, a small quantity of free 'cerotic acid,and myricyl alcohol. The physical properties are: melting point, 84-91C.; specific gravity, 0.99; acid number, 4-9; saponification number,78-87; soluble in'hot alcohol and in benzene, ether dioxane, andisopropyl ether.

'(b) Parafiin'.This is a petroleum wax obtained from the high boilingfractions of petroleum. It is a mixture of a great number of saturatedhydrocarbons. Its physical properties are: melting range, 43-66 C.;specific gravity, 0.88-0.92 at ordinary temperatures; acid number,saponification number, 0; soluble in benzene ether, chloroform, andturpentine.

' '(c) Beeswax.This is 'an insect wax. Chemically, it

is composed of myricyl palmitate, cerotic and homologous acids, andsmall amounts of hydrocarbons, cholesterol esters, ceryl alcohols,pollen, and'resins. The physical properties are: 'melting point, 63-70C.; specific gravity, 0.95 2-0L957; acid number, 16-20; saponificationnumber, 90-96; soluble in benzene, carbon tetrachloride,chloroformfdioxane, acetone, and ether.

(d) Spermaceti.This is an animal wax obtained from the sperm whale. Itis composed of cetyl palmitate, cetyl alcohol, and numerous esters ofhigh-molecular weight fatty acids. The'physical properties are: meltingpoint, 42-49" C.; specific gravity, 0945-0960; acid number, 0.5-1.1;saponification number, 122-129; soluble in hot alcohol, ether,chloroform, and carbon disulfide.

'(e) M0ntai1.This is a mineral wax obtained by sol vent extraction ofwoody coals or lignite. It is a monohydric ester of a'high-molecularweight acid. The physical properties are: melting point, 72-92 C.;specific gravity,l.0.; acid number, 15-85; saponification number, 58-89;soluble in' benzene, chloroform, naphtha, and isopropyl ether.

f) High-molecular weight acids and alcohols-A number of alcohols andacids havewax-likeproperties. These include cetyl and stearyl alcoholsand stearic, palmitic, and myris'tic acids.

(g) High-molecular weight esters-The stearates of polyhydric'alcohols,such as ethylene glycol and diethylene glycol are high-molecular weightproducts of a waxlike nature.

(h) Carb0waxes.-'Ihese are synthetic Waxes sold by Carbide and CarbonChemicals Company and comprise a series of high-molecular weightpolyethylene glycols. These waxes have a melting point range of 34-55 C.and a density range of 1.15-1.20. They are water-soluble.

"(i) Acrawaxes.These waxes are produced and sold by Glyco ProductsCompany in threegrades: Acrawax, Acrawax B, and Acrawax C. They arecomplex nitrogen derivatives of high-molecular weight fatty acids. Thephysical properties of these three waxes range as follows: meltingpoint, 95-139 C.; specific gravity, 0.98-1.05; soluble in hot toluene,turpentine, and mineral oil.

(j) CastorWam-This is a hydrogenated castor oil produced and sold byBaker Castor Oil Company. The physical properties are: melting point,86-88 C.; saponification'number, 175-185; acid number, 2; insoluble inmost solvents.

(k) P0lyethylerte.-Tl1isis a high-molecular weight polymer of ethylenebeing produced by a number of chemical companies. It s melting point isl05-110 C. It is soluble in hot benzene and toluene but insoluble inpractically all organic solvents in the cold,

Thus, irrespective of the particular method used of applying the wax, orthe particular wax used, the fibers are readily wrapped in conventionalequipment to form a smoke filtering element. The resultant filterelement comprises a structurally unitary rod like mass of fibers with awrapper encircling the mass, each fiber of the mass being substantiallycoextensive therewith, the fibers as a whole being all substantiallyaligned longitudinally of the mass. However, substantially each of theindividual fibers has a plurality of short portions thereof crimped intodiverging and converging relationship to the main fiber axis. Aplurality of the fibers have surface bonds to contiguous fibers atrandom points of contact. This bonding may be accomplished eitherthrough the presence of plasticizer or the wax or a combination ofwax-plasticizer.

As indicated above, we prefer to use in the instant invention fibers ofcellulose esters and particularly cellulose acetate fibers which have acertain amount of crimp and have the property of bonding to some extent.to adjacent fibers, either because of the thermoplastic properties ofthe fibers or the addition of plasticizer or the presenceo f wax of thepresent invention, or by combiriation of the foregoing.

For a further understanding of our invention reference may be made tothe following examples which are set forth primarily for the purpose ofdisclosing our preferred embodiments. Y

" v Example I A tow of cellulose acetate yarn containing approximately20,000 fibers of five denier per filament was slowly pulled over acompressed air device which spread out the fibers to a width of sixinches. While the tow was in, this spread condition it was sprayed witha molten petroleum wax heated to C. After this spreading and sprayingtreatment, the tow was pulled back to its original shape and fed into aconventional cigarette make up machine which cut and paper-wrapped itinto rods of 8.1 mm. diameter and 71 mm. length. The rods contained 24parts wax and 76 parts cellulose acetate by weight. The rods were cutinto 12-min. filter tips. These tips were attached to standard Americancigarettes by means of an adhesive tape (Scotch tape) and the cigaretteswere smoked on a smoking machine similar in design and operation tothesmoking machine described-by J. A. Bradford, W. R. Harlan, and H. R.Hammer in Industrial and Engineering Chemistry, vol. 28, pp. 836-9(1936). The results of the smoking experiment were compared with thoseobtained from smoking the same brand of cigarettes containing 12-min.filter tips of the same tow of cellulose acetate fibers without theaddition of the wax.

Mg. of tars Mg. ofnieobtained otine obfrom the tained from Type ofcigarette tip (12 mm.) collected the colsmoke of lasted- 10 filteredsmoke of 10 cigarettes filtered cigarettes Cellulose acetate tow 132 20Cellulose acetate tow containing 24% petroleumwax 107 18 through onecigarette. On this basis, the average prestnre drop of the abovecigarettes with a filter-of cellulose acetate tow was 4.0 inchesofwater; the average pressure drop was 4.3 inches of water when a filterof cellulose acetate tow With 24% wax additive was tested.

Example In accordance with this example, cellulose acetate towapproximately the same as that described in Example I was spread bymeans of compressed air. The spread tow was treated with a wax known ascastor wax to the extent of about'24% of the weightof the fibers.Thereafter the castor wax treated fibers were fed into conventionalmafiltered cigarettes were smoked on the smoking machine.

chin'ery for forming and wrapping the fibers into filter elements. Thefilter elements were attached to cigarettes and tested in the smokingmachine. The test indicated that the wax treated filters 'of the presentinvention improvedthe removal of undesired compounds. That is, 7% moretar was removed with the filters of the present invention as comparedwith a filter that had no wax treatment; This was some 25% greater tarremoval than with 'a regular cigarette having no filter whatsoever. Inaddittion to giving improved removability of tar, the filters of thepresent invention were firmer and stifier than prior art filters. Thisfirmness persisted throughout the smoking operation and the filters ofthe present invention did not become soft and soggy.

Examplef LIII A tow of cellulose acetate yarn containing approximately10,000 filaments of 8 denier per filament was slowly pulled over acompressed air device which spread out the fibers to a width of sixinches. While the tow was in this spread condition, it was dusted withpowdered (300 mesh) stearic acid. After this spreading and dustingtreatment, the tow was pulled back to its original shape and fed into aconventional cigarette make-up machine which cut and paper Wrapped itinto rods of 8.1-mm. diameter and 71-11'1111. length. The rods contained25 parts stearic acid and 75 parts cellulose acetate fibers by weight.These soft rods were heated at 85 C. for ten minutes (melting point ofstearic acid, 69-70" C.) 'in a drying oven and then allowed to return toroom temperature. On cooling, the rods became quite firm. These firmrods were cut into l2-mm. filter tips. These tips were attached tostandard American cigarettes by means of a cellulose tape and thecigarettes were smoked on the smoking machine. The results of thesmoking experiment were compared with those obtained from smoking thesame brand of cigarettes containing l2-mm. filter tips of the same towof cellulose acetate fibers without the addition of the wax.

Average pressure tained drop of from the the cigarcollected ettes smokeof (inches of 10 filtered water) cigarettes Mg. tars obtained from thecollected smoke of 10 filtered cigarettes Mg. nicotine ob- Type ofcigarette tip (12 mm.)

Cellulose acetate tow Cellulose acetate tow containing 25% stearic acidIt can be seen from this Example III that the filter containing thestearic acid wax removed substantially more tar and nicotine than thecorresponding control filter without the Wax. Also, this filter wasfirmer and did not become soggy.

Example IV The results of the smoking experiment were compared withthose obtained from smoking the same brand of ciggarette containing12-min. filter tips of the same tow of regenerated cellulose without theaddition of the wax.

Mg. nicotine ob- Average pressure drop of the cigar- Mg. tars obtainedfrom the collected smoke of 10 filtered cigarettes tained from thecollected smoke of 10 filtered cigarettes Type of cigarette tip (12 mm.)

' ettes (inches of water) Regenerated cellulose tow Regeneratedcellulose. tow conta mg 18% carnauba wax 3 While we prefer tomanufacture our filter from crimped,

oriented, longitudinally positioned cellulose acetate fibers, we havefound that the wax improves (other types of fibers such as viscosefibers.

We claim:

1. A tobacco smoke filtering element comprised of a unitary rod-likebundle of at least 10 ,000 continuous cellulose acetate filaments, thebundle being approximately 8.1 mm. in diameter, the filaments of thebundle being longitudinally aligned and coextensive with the length ofthe filter element, and the filaments having nonoriented short portionsthereof crimped into diverging and converging relationship to the mainfilament alignment, the spacing of the adjacent aligned continuousfilaments providing longitudinal passages for smoke through the bundle,the filter element being further characterized in that the aforesaidfilaments carry and have relatively uniformly distributed on thesurfaces of the filament 130% by weight of a wax.

2. A tobacco smoke filtering element comprised of a structurally unitaryrod-like bundle of at least 10,000 continuous cellulose acetatefilaments of a denier of approximately 5-8 per filament, 130% by weightof a wax uniformly deposited on the surface of the filaments and awrapper encircling the bundle, each wax-covered filament of the bundlebeing substantially co-extensive with the length of the filter element,the filaments as a whole being in substantial alignment longitudinallyof the filter element and each of the individual filaments of the bundlehaving a plurality of short portions thereof crimped into diverging andconverging relationship to the main filter element axis, the spacing ofgroups of adjacent continuous filaments providing longitudinal passagesfor smoke through the bundle, the wax occupying positions in andpartially blocking said passages.

3. A filter element in accordance with claim 2 wherein the wax isparafiin wax.

4. A filter element in accordance with claim 2. wherein the Wax iscastor wax.

5. A tobacco smoke filtering element comprised of a rod-like bundle ofat least several thousand continuous crimped synthetic filaments of adenier per filament not greater than 8, l30% by weight of a wax in theform of finely divided particles substantially uniformly disposed on thesurface of the filaments and a wrapper encircling the bundle, eachwax-covered filament of the bundle being substantially coextensive withthe length of the filter element, the filaments as a whole being insubstanalignrnentlongitudinally of'the filter element and each of theindividual filaments. of the bundle having a plurality. of: shortportions thereof crimped into diverging and. converging relationship tothe main filter element axis, the spacing of groups of adjacentcontinuous filaments. providing longitudinal passages for smoke throughthe bundle, the wax occupying positions in and partially blocking saidpassages.

6. A tobacco smoke filtering element comprised of a rod-like bundle ofat least several thousand continuous crimped. cellulose acetatefilaments, 130% by weight of wax in the form of finely divided.particles disposed on the surface ofi the filaments and relativelyfirmly bonded thereto and a wrapper encircling the bundle, eachwaxcovered filament; of the bundle being substantially coextensive withthe length of the filter element, the filaments as a whole being insubstantial alignment longitudinally of the filter element and each ofthe individual filaments of the bundle having a plurality of shortportions thereof erimped into diverging and converging relationship tothe main filter element axis, the spacing of groups of adjacentcontinuous filaments providing longitudinal passages for smoke throughthe bundle, the wax occupying positions in and partially blocking saidpassages.

7 z A filter element in accordance with claim 6 wherein the finelydivided wax is from the group consisting of carnauba, parafiin, bees,spermaceti, montan, carbo, acra, castor and polyolefin waxes.

8. A filter element in accordance with claim6 wherein the wax is astearyl alcohol.

9. A filter element in accordance with claim 6 wherein the wax is apolyolefin wax.

10. A filter element in accordance with claim 6 wherein there is acontent of plasticizer present.

References Cited in the file of this patent UNITED STATES PATENTS 1Demouth Oct. 15, 1889v Sundheim Mar. 10, 1896 Linnekogel Nov. 4, 1902Minton July 25, 1933 Reed Apr. 5, 1938 Strauch Sept. 5, 1939 Neville etal. July 9, 1940 Knewstubb et al. July 3, 1951v MacHenry Sept. 7., 1954Taylor et a1 May 3, 1955 Von Reis et al Oct.25, 1955 Jacobset al. June19, 1956 Hackney et al Dec. 18, 1956 Taylor et al. Apr. 23, 1957 FOREIGNPATENTS Great Britain June 13, 1929 Great Britain May 25, 1949 OTHERREFERENCES Matthews: Textile Fibers, pages 266, 207, 267 and 268,

published 1947 by John Wiley & Sons, Inc., New York.

The Modern Textile Dictionary, by G. E. Linton, page 5; published 1954by Duell, Sloan and Pierce Little,

Brown and Co., New York, NY.

1. A TOBACCO SMOKE FILTERING ELEMENT COMPRISED OF A UNITARY ROD-LIKEBUNDLE OF AT LEAST 10,000 CONTINUOUS CELLULOSE ACETATE FILAMENTS, THEBUNDLE BEING APPROXIMATELY 8.1 MM. IN DIAMETER, THE FILAMENTS OF THEBUNDLE BEING LONGITUDINALLY ALIGNED AND COEXTENSIVE WITH THE LENGTH OFTHE FILTER ELEMENT, AND THE FILAMENTS HAVING NONORIENTED SHORT PORTIONSTHEREOF CRIMPED INTO DIVERGING AND CONVERGING RELATIONSHIP TO THE MAINFILAMENT ALIGNMENT, THE SPACING OF THE ADJACENT ALIGNED CONTINUOUSFILAMENTS PROVIDING LONGITUDINAL PASSAGES FOR SMOKE THROUGH THE BUNDLE,THE FILTER ELEMENT BEING FURTHER CHARACTERIZED IN THAT THE AFORESAIDFILAMENTS CARRY AND HAVE RELATIVELY UNIFORMLY DISTRIBUTED ON THESURFACES OF THE FILAMENT 1-30% BY WEIGHT OF A WAX.